Eating raisins and soy appears to help ward off high blood pressure, a key risk factor in heart disease, according to two studies presented at a major US cardiology conference recently. Munching on a handful of raisins three times a day helped people with slightly elevated blood pressure to lower their number after several weeks, said one of the studies presented at the American College of Cardiology conference.

The randomized clinical trial – believed to be the first formal measurement of raisins’ benefits on blood pressure – involved 46 people with a condition known as pre-hypertension. That means their blood pressure ranged from the normal 120 over 80 millimetres of mercury (mmHg) to 139/ 89mmHg or just higher than normal.

Compared to people who snacked on cookies or crackers, the raisin-eating group saw significant drops in blood pressure, in some cases lowering the top number, or systolic pressure, by 10.2 or 7% over the 12-week study.

Researchers are not sure exactly why the raisins work so well, but their think it may have to do with the high level of potassium in the shrivelled, dried grapes. Raisins are packed with potassium, which is known to lower blood pressure. They are also a good source of antioxidant dietary fibre that may favourably alter the biochemistry of blood vessels, causing them to be less stiff, which in turn, may reduce blood pressure.
A handful of about 60 raisins contain a gramme of fibre and 212mg of potassium. Raisins are often recommended as part of a high-fibre, low-fat diet to reduce blood pressure. A second study on soy that began in 1985 showed that daily intake of foods like tofu, peanuts and green tea helped lower blood pressure in more than 5,100 white and African-American people aged 18 to 30.

The study was based on self-reported data about on the food the participants ate. Those who consumed about 2.5 or more milligrammes of isoflavones, a key component in soy, per day had significantly lower systolic blood pressure – an average of 5.5 mmHg lower than those who ate less than 0.33mg per day.

That daily level should not be hard for most people to reach – a glass of soy milk contains about 22mg of isoflavones, or nearly 10 times the amount needed to see an effect, according to the research. The results strongly suggest a blood pressure benefit for moderate amounts of dietary isoflavone intake in young adults.

Eating soy could be a way for people with slightly elevated blood pressure to avoid progressing to high blood pressure and potentially ward off the need to take medications.

Soy and the isoflavones it contains work by boosting enzymes that create nitric oxide, which in turn helps to widen blood vessels and reduce blood pressure.

Based on the result and those of previous studies, it encourages the average adult to consider including moderate amounts of soy products in a healthy, well-balanced die to reduce the chances of developing high blood pressure.